Prevalence of non-aromatic carbonaceous molecules in the inner regions of circumstellar envelopes

Autor: Mario Accolla, Koen Lauwaet, José A. Martín-Gago, Jesús Manuel Sobrado, Roberto Otero, Gonzalo Santoro, Gary Ellis, Ramón J. Peláez, José Cernicharo, Isabel Tanarro, Hassan Sabbah, Alberto Martín-Jiménez, Christine Joblin, Marcelino Agúndez, Víctor J. Herrero, Lidia Martínez, Pablo Merino
Přispěvatelé: European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), Comunidad de Madrid
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Nature astronomy
Repositorio Institucional del Instituto Madrileño de Estudios Avanzados en Nanociencia
instname
Digital.CSIC. Repositorio Institucional del CSIC
ISSN: 2397-3366
Popis: 9 pags., 6 figs.
Evolved stars are foundries of chemical complexity, gas and dust that provide the building blocks of planets and life, and dust nucleation first occurs in their photosphere. The circumstellar regions enveloping these stars, despite their importance, remain hidden to many observations, and dust formation processes are therefore still poorly understood. Laboratory astrophysics provides complementary routes to unveil these chemical processes, but most experiments rely on combustion or plasma decomposition of molecular precursors under physical conditions far removed from those in space. To reproduce and characterize the bottom-up dust formation process, we have built an ultra-high vacuum machine combining atomic gas aggregation with advanced in situ characterization techniques. We show that carbonaceous dust analogues that formed from low-pressure gas-phase condensation of carbon atoms in a hydrogen atmosphere, in a ratio of carbon to molecular hydrogen similar to that reported for evolved stars, lead to the formation of amorphous carbon nanograins and aliphatic carbon clusters. Aromatic species and fullerenes do not form effectively under these conditions, raising implications for a revision of the chemical mechanisms taking place in circumstellar envelopes.
We thank the European Research Council for funding support under Synergy Grant ERC-2013-SyG, G.A. 610256 (NANOCOSMOS). We also acknowledge partial support from the Spanish Research Agency (AEI) through grants MAT2017-85089-c2-1R, FIS2016-77578-R and FIS2016-77726-C3-1-P. Support from the FotoArt-CM Project (P2018/NMT-4367) through the Program of R&D activities between research groups in Technologies 2013, cofinanced by European Structural Funds, is also recognized.
Databáze: OpenAIRE
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